One particular use case for these is escape sequences -- and to that
end, I'm also adding `\e` as a shorthand for `\x1b`.
Change-Id: Id000000040ea6fd8e2d720219931485960c570dd
It's inconvenient that we have to quote glob patterns as 'glob:"*.rs"'. Suppose
filesets are usually specified in shell, it's better to allow unquoted strings
if possible. This change also means we'll probably abandon #2101 "make the
parsing of string arguments stricter."
Note that we can no longer introduce ? operator or [] subscript syntax in
filesets.
Closes#4053
Since fileset and revset languages are syntactically close, we can reparse
revset expression as a fileset. This might sound a bit scary, but helps
eliminate nested quoting like file("~glob:'*.rs'"). One oddity exists in alias
substitution, though. Another possible problem is that we'll need to add fake
operator parsing rules if we introduce incompatibility in fileset, or want to
embed revset expressions in a fileset.
Since "file(x, y)" is equivalent to "file(x|y)", the former will be deprecated.
I'll probably add a mechanism to collect warnings during parsing.
I'm going to extract generic alias substitution functions, and these AST types
will be accessed there. Revset parsing will also be migrated to the generic
functions.
This will help extract common FunctionCallNode<'i, T> type. We don't need
freedom of arbitrary error type choices, but implementing From<_> is the
easiest option I can think of. Another option is to constrain error type by
the expression type T through "T::ParseError: ArgumentsParseError" or
something, but it seemed a bit weird that we have to use trait just for that.
Since fileset/revset/template expressions are specified as command-line
arguments, it's sometimes convenient to use single quotes instead of double
quotes. Various scripting languages parse single-quoted strings in various ways,
but I choose the TOML rule because it's simple and practically useful. TOML is
our config language, so copying the TOML syntax would be less surprising than
borrowing it from another language.
https://github.com/toml-lang/toml/issues/188
While I like strict parsing, it's not uncommon that we have to deal with file
names containing spaces, and doubly-quoted strings such as '"Foo Bar"' look
ugly. So, this patch adds an exception that accepts top-level bare strings.
This parsing rule is specific to command arguments, and won't be enabled when
loading fileset aliases.
Since fileset is primarily used in CLI, it's better to avoid inner quoting if
possible. For example, ".." would have to be quoted in the original grammar
derived from the revset.
This patch also adds a stricter version of an identifier rule. If we add a
symbol alias, it will follow the "strict_identifier" rule.
The fileset grammar is basically a stripped-down version of the revset grammar,
with a few adjustments:
* extract function call to "function" rule (like templater)
* inline "symbol" rule (because "identifier" and "string" should be treated
differently at the early parsing stage.)
The parser will have a separate name resolution stage. This will help to do
alias substitution properly. I'll probably rewrite the revset parser in the
same way. It will also help if we want to embed fileset expression in file()
revset.
